1. Field of the Invention
This invention relates generally to ore dressing and to concentration of metal values in ores by flotation. More particularly the invention provides new and valuable methods of recovering metal values from ores, whereby froth flotation of a slurry of the ore is conducted in the presence of a collector comprising an organic thionocarbamate in admixture with an inert, organic liquid as extender therefor.
2. Description of the Prior Art
The flotation method of concentrating metal values in ores is based on the fact that when air bubbles are introduced into a ground ore pulp, particles of some minerals will become attached to the bubbles, whereas other minerals will not become so attached and remain in the pulp. Certain chemicals facilitate flotation by conferring adherency and/or water repellency to surfaces of minerals to be floated, and such chemicals have been generally called "promoters" or "collectors". Herein, they will be referred to as collectors. It is customary in the art to employ other reagents in flotation; for example, there may also be used materials which serve as frothers, activators, depressants, or modifying agents. The presence or absence of such reagents and their nature will vary with ores and reaction conditions, and selection of such other additives for serving differing functions can be readily arrived at by routine experimentation.
In the prior art, numerous materials have been reported to serve as collectors; for example, the xanthates, the thiocarbanilides and the thionocarbamates. Industrially, collectors for use in flotation are of great importance because even a very small improvement in the efficacy of the collector can have immense commercial effect. With the growing current practice of tailings retreatment, the cost efficiency of the collector becomes increasingly significant. Unfortunately, the more valuable collectors, for example, the organic thionocarbamates are expensive materials. Heretofore, research which has been directed at providing inexpensive, readily available materials having collector efficacy has not been very successful.